Slain student Jamie Gao appeared in a Sydney court on kidnapping and assault charges less than a fortnight before his body was found dumped off Cronulla.

The 20-year-old appeared at Downing Centre Local Court on May 13 charged with kidnapping a young man at Carlton, in Sydney's south.

Gao allegedly kidnapped the man on January 9 with two minors for the purposes of obtaining information from the victim, court documents revealed.

The victim allegedly suffered bodily harm during the incident.


Gao was also charged with conspiracy to assault another young man on the same night, also at Carlton.

The charges against Gao are understood to be unrelated to his death.

Police have indicated the charges were linked to a domestic situation and the breakdown of a relationship.

Gao's body was found on Monday about 1.5km off Cronulla, wrapped in a blue tarpaulin and chains.

It's alleged the university student, from Hurstville, in Sydney's south, was shot twice in the chest before being dumped at sea after a botched A$3 million ($3.3 million) drug deal.

Former NSW detectives Roger Rogerson, 73, and Glen McNamara, 55, have been charged with his murder and supply of drugs.